Hypericin- and Δ-aminolevulinic acid-induced phototoxicity in squamous and adenocarcinoma cell lines of the esophagus

Background & Aims: Photodynamic therapy (PDT) is an effective treatment modality in high grade dysplasia and early esophageal cancer. PDT involves the activation of a photosensitizing drug in order to cause tumor necrosis . The currently used photosensitizers of the first generation (e.g. porfimer sodium, haematoporphyrin derivate) cause systemic photosensitization for up to two months and esophageal stricture formation in up to a third of the patients. Therefore, the aim of our study was to evaluate the efficacy of two new photosens itizers